With the rapid development of multistage hydraulic fracturing in unconventional reservoirs, a significant increase of freshwater consumption has been observed in many oilfield locations. To reduce the high cost associated with obtaining fresh water and use alternate water sources, utilization of produced water or seawater as the base fluid for fracturing has attracted considerable research interest. Some components of fracturing fluids, such as the friction reducer, showed reduced performance in produced water or seawater due to its higher salt content vs. fresh water. The objective of this study is to identify additives, which can improve the performance of conventional polyacrylamide friction reducers under high salinity conditions.<br/>A series of new friction reducer packages were prepared through the incorporation of nanocellulose additives to the friction reducer package. The effect of additive type and loading level on friction reducer performance under different salinity conditions was studied. Compared to standard friction reducers based on only acrylamide copolymers, the new friction reducer, a blend of acrylamide copolymers and nanocellulose, showed improved salt tolerance properties for maintaining fluid viscosity and friction reduction. Fluids with higher viscosity were obtained through the incorporation of nanocellulose. The fluid also showed less pronounced viscosity drop when salinity of the base fluid increased in comparison to fluid containing only acrylamide copolymer. Additionally, the new friction reducer package maintained good friction reduction performance in synthetic saltwater, with friction reduction reaching around 70% in flow loop studies. These properties allow the potential utilization of nanocellulose/acrylamide copolymers blends as the friction reducer for slickwater treatment when water with less than ideal quality or higher salinity is used in the fracturing job.

Novel additive to improve friction reducer salt tolerance

ACS Fall 2021

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